The present invention pertains to a portable hydrogen generation system and method which can power internal combustion engines on-board vehicles such as automobiles. Furthermore, this hydrogen generation system can supply hydrogen to feed fuel cells. The fuel supplied to the portable hydrogen generation system comes in the form of an emulsion that consists of metal powder pre-mixed with oil. The metal emulsion can be precisely injected into the hydrogen generation system based on demand. The hydrogen is generated from the reactions between an alkaline metal, such as sodium and water, or the reaction between alkaline hydroxide solution and a metal such as iron or aluminum.
It is well known that hydrogen can be used to fuel internal combustion engines or to feed fuel cells, and it has been commercially produced as a byproduct from chlorine-alkali electrolysis or through large-scale production through a steam-carbon reaction. However, hydrogen is bulky and a real challenge to store. Such an obstacle can be overcome by hydrogen generation on-situ and by on demand delivery. Some processes have been disclosed as producing hydrogen from the reaction between an alkali metal and water. However, such disclosure fails to show that metal in emulsion can facilitate metering-on-demand and precise injection into an internal combustion engine. The on demand hydrogen generation systems have been exemplified by others but show systems which do not use a metal emulsion. For instance, one particular system utilizes a membrane to separate a water container from a metal hydride or alkali metal with water slowly diffusing through the membrane to achieve a chemical reaction. However, the system is unreliable. In the case of membrane rupture, all alkali metal or metal hydride would be instantly be exposed to water and result in an uncontrollable generation of the hydrogen. This is totally unsuitable for use in automobiles and motor vehicles. Another drawback of the membrane is the possibility of membrane clog after prolonged use.
The use of hydrogen as fuel for internal combustion engines or for fuel cells to run an electric car has also been disclosed. However, there is still no teaching of the use of metal emulsions which can be metered and fed precisely on demand to the hydrogen generator and at the same time have low temperature reactions with a high rate of hydrogen generation. Some others have used hydrochloric acid to react with a pure metal to generate hydrogen. There, again no metal emulsion is involved.
In other teachings, activated iron is reacted with heated water for hydrogen generation. However, again there is no use of metal emulsion. Others seek to generate hydrogen from metal hydrides and water. The diffusion of water into metal hydride granules results in hydroxide or oxide which may result in resistance to water diffusion and an incomplete conversion of rather expensive materials. There is thus a need for complete conversion of metal to hydrogen. Another example of the in-situ-hydrogen-generation for internal combustion engines shows hydrogen generated by the reaction of non-compressed packed-iron-powder with alkaline hydroxide as a catalyst at temperatures lower than 250 degrees C. However, the quantity of iron or aluminum in emulsion form being precisely metered into the reactor and completely reacted according to the demand of the internal combustion engine, has not been observed.
Others suggest that any active material, such as sodium, may be coated with an impervious material, such as plastics or aluminum film. The pellet coating can be broken by an electrical current or a mechanical means, such as a knife, and then the sodium is exposed to water to generate hydrogen on-board of a motor vehicle. However, such inventions can only supply the fuel in large increments, due to the size of the pellets, but not continuously. In particular, some have shown reacting iron with water in the presence of an alkali hydroxide as a catalyst to generate hydrogen, then, using it to feed a fuel cell. The electricity produced is utilized to run an electric car. However, such an invention does not have the benefits of simplicity of a mechanical arrangement and the precision and continuity of metering the fuel according to the demand of the engine. In addition, neither is there a high rate of hydrogen production nor the desired lowered temperature for reactions to take place between metal emulsions and water seen in such inventions.
The principal object of the present invention is to provide a fuel for an in-situ-hydrogen-generation system using a metal emulsion that can be continuously metered and precisely fed into a reactor, in which the metal is rapidly and completely reacted with water or hydroxide solution. The hydrogen generated is used to operate an internal combustion engine or to fuel a fuel cell. The electricity generated from the fuel cell can be used to drive an electric car or other electrical devices.
Another object of the present invention is to prepare the metal fuel (finely divided iron or aluminum or alkali metals) in paste form to prevent pre-usage contamination of the metal by water vapor or oxygen in the air. The said paste (or emulsion) has a certain consistency to allow it to be fed or injected smoothly, precisely, and continuously. The metal fuel emulsion may be contained in cartridges.
Still another object of the present invention is to provide for the said hydrogen generation system, a microprocessor controlled system to orchestrate the smooth operations of the metal to hydrogen conversion. The microprocessor timely opens and closes the delivery valves of emulsion cartridges according to the operating conditions of the internal combustion engine which the hydrogen generation system serves. It also controls the supply of water (or hydroxide solution) to the reactor and the discharging of the waste reaction products.
Still another object of the present invention is to provide a stirrer for the reacting tank to promote a complete reaction between the metal powder granules and water (or hydroxide solution). Thus, the rapid reaction and the complete conversion of the metal to hydrogen are assured.
Yet, another object of the present invention is to provide for instant pure hydrogen generation using reactions at low temperatures, for instance water at or near room temperature, to react with metal fuel so as to result in a higher rate of hydrogen generation than currently observed, making it highly desirable for use with automobiles. The pure hydrogen is also preferably generated at or near room temperature.
Further, it is another embodiment of the present invention that the reaction tank of the system is kept at a constant and desirable temperature through the use of a variable speed blower to remove excess heat generated by the reaction tank.
These and other embodiments of the present invention are further made apparent, in the remainder of the present document, to those of ordinary skill in the art.